Co-Optima Boosted Spark-Ignition and Multi-Mode Combustion, Part 3

Scott Curran (ORNL) - PresenterChris Kolodziej, Ashish Shah (ANL) Magnus Sjöberg (SNL) Sibendu Som, Noah Van Dam (ANL)

June 20, 2018

FY18 Vehicle Technologies Office Annual Merit Reviewbetter fuels | better vehicles | sooner

Project ID: FT055

This presentation does not contain any proprietary, confidential, or otherwise restricted information.

VTO Program Managers: Gurpreet Singh, Kevin Stork, & Michael Weismiller

Overview: Focus Light-Duty DISI → Multi-Mode

2

Barriers**

Budget Partners• Co-optima partners include nine national labs, 13

universities, external advisory board, and stakeholders (77 organizations)

• 15 Industry partners in the AEC MOU• Task specific partners• General Motors - Hardware• Toyota – Funds-in knock project • Ford support for engine modifications • LLNL (W. Pitz et al.) – Chemical kinetics• G.2.5 Edwards - Toolkit• + Many more – details in later slides

Task FY16 FY17 FY 18E.1.1.3: Optical Diag.: Fuel Effects on Lean Homogen. and Stratified $652K $652K $475K

E.1.1.4: LD DISI relevance of RON & MON for lean/dilute + Knock

$300K $300K $155K

G.2.1: DISI engine simulations $50K $255K $165K

E.1.2.5: Fuel properties enhance mixed-mode ACI/SI NA NA $315k

E.1.2.6: Multi-mode SI/ACI –stratification/fuel/dilute interact NA NA $325K

Advanced Engine Development: Transition from LD SI & ACI to ACI/SI Multi-Mode

• 2020/2025 Stretch Efficiency Goals for downsize boosted engines

• Robust lean-burn and EGR-diluted combustion technology and controls

• Determine the factors limiting range of LTC /develop methods for extending the limits

• Understanding impact of likely future fuels on LTC

* Start and end dates refer to three-year life cycle of DOE lab-call projects. Co-Optima is expected to extend past the end of FY18

Timeline* Task FY16 FY17 FY 18 FY19 FY20E.1.1.3: SNL Start End New Proposal

E.1.1.4: SNL Start End

G.2.1: ANL Start End New Proposal

E.1.2.5: ANL Start

E.1.2.6: ORNL Start

SI

MM

**https://www.energy.gov/sites/prod/files/2018/03/f49/ACEC_TT_Roadmap_2018.pdf

MM

Relevance

3

• Increased fuel economy requires engines with higher thermal efficiency, while complying with stringent exhaust requirements for clean air– Mirrors the programmatic transition in Co-Optima from downsized boosted and light-duty ACI

tasks to multi-mode SI-ACI R&D • These light-duty engine development and computational toolkit research tasks support:

– Near-term Co-Optima fuel-economy targets for conventional boosted SI– Longer-term development of fuels for advanced highly efficient SI combustion

Boosted SI Multi-modeSI / ACI

Light-Duty

• Boosted SI (DISI)– Continue to perform fuel studies to address barriers for

achieving high thermal efficiency for boosted for boosted stoichiometric SI operation

– Emissions mitigation for more efficient stratified-charge SI operation

– Efficiency gains for ultra-lean well-mixed SI operation that utilizes mixed-mode combustion (with transition from deflagration to autoignition)

• Multi-Mode (SI-ACI) – Address barriers to add to knowledge-base and modeling

capabilities for both SI and ACI modes– Inform industry of fuel effects on multi-mode– Link to emissions controls/ toolkit tasks for accelerating

development of multi-mode and addressing barriersOverall Co-Optima Relevance Farrell FT037

Milestones: Met or On TrackMonth/Year Description of Milestone StatusMarch 2017, SNLE.1.1.4

Provide fuel-efficiency and exhaust emissions data for SI operation for AKI87 and RON 98 to ASSERT team

Met

March 2017, ANLG.2.1

Sensitivities to fuel properties at validation points for the SNL DISI engine

Met

June 2017, ANLG.2.1

Dataset of simulations with virtual fuels to evaluate fuel property hypothesis

Met

Sept 2017, ANLG.2.1

Sensitives to fuel properties at validation points for ACI engine

Met

March 2018, SNLE.1.1.3

Fuel sooting behavior- Compare sooting tendencies of three Tier 3 fuel blends for stratified-charge SI operation.

Met

Sept 2018, ANLE.1.2.5

Evaluate relationship between fuel RON-MON sensitivity and temperature delta for ACI and SI

On Track

Sept 2018, ORNLE.1.2.6

Make recommendation on viability of 2 step VCR as multi-mode enabler

On Track

4

Multi-mode engine experiments to overcome technical barriers for achieving multi-mode goals

Overall Technical Approach: 5 tasks/ 3 labs + many collaborations

5

Combine metal- and optical-engine experiments and modeling: DISI combustion processes

Enhance understanding and accelerate development through linked modeling efforts

Utilize Co-Optima core fuels, promising blendstocks and custom blends as needed

E.1.2.5: ANLE.1.1.4: SNL E.1.2.6: ORNLE.1.1.3: SNL

G.2.1: ANL

Temp-Press Trajectory Framework

CollaborativeKinetics/ Toolkit tasks

Emissions Controls andCharacterization Tasks

• Drop-down single-cylinder engine. Bore: 86 mm, Stroke:95 mm, CR:12, 0.55L.

• Piston bowl and closely located spark and injector ⇒ Highly relevant for stratified SI. Use early injection for well-mixed operation.

• Identical geometry for all-metal testingand optical diagnostics.– PIV – Flows, Mie or Back Illumination -

Liquid Spray, RIM - Wall Wetting, IR - Fuel Vapor. Plasma & flame imaging.

• Combine metal- and optical-engine experiments and modeling to develop a broad understanding of the impact of fuel properties on DISI combustion processes.– Utilize Co-Optima core fuels and

promising blendstocks in mid-levelRON98 surrogate blends.

• First, conduct performance testing with all-metal engine over wide ranges of conditions.– Assess relevance of Octane-Index

framework for stoichiometric knock and lean mixed-mode combustion (SACI).

– Relate exhaust smoke emissions to Particulate Matter Index (PMI).

• Second, apply optical diagnostics to:– Clarify shortcomings of PMI.– Probe spray development.– Provide conceptual understanding of

advanced SI combustion modes.

Approach – SNL: Sjöberg

6

(SACI) = spark-assisted compression ignition RIM = refractive index matchingPIV = particle image velocimetry

CR = compression ratioIR = infrared

2 Turbulence models• LES – more flow details• RANS – higher throughput

ANL- CFD: Approach/Workflow

7

Motored Flow Combustion

Spray Validation

IMEP

CA50

ThermalStratification

Presented 2017 AMR

ft055

Multiple ConditionsMultiple P-T trajectories

2 Turbulence-chemistry interaction models• Well-stirred Reactor – easier implementation• G-equation – improved flame description

Presented 2017 AMR ft055

Partially Presented 2017 AMR ft055

Motored withFuel Injection

Merit FunctionSlope Analysis

Global SensitivityAnalysis

ORNL - Curran• Multi-mode SI/ACI: stratification/ fuel/ dilute

interactions– Bridge foundational DOE CO-Optima research

into fuel-property impacts on boosted SI efficiency and ACI efficiency and help understand fuel effects w/ tumble dominated combustion systems operating in both SI and ACI modes

– Focus on quantifying the effects of octane number, S, and HOVat “SI” and “ACI” compression ratios @ multi-mode conditions.

– Leverages boosted SI work by Sluder (same base engine)

ANL – Kolodziej• Fuel Properties which Enhance Mixed-

Mode ACI/SI Engine Operation– Goal: Define a ∆T metric of low/high S

fuels, using Co-Optima alkylate, E30, and aromatic gasolines

– Question: “Does RON-MON sensitivity capture fuel auto-ignition and knock temperature dependencies?”

– Engine parameter of interest: Temperature (modified by intake air heating)

Approach – Multi-Mode Projects:2 - Metal single-cyl. SI base engines (ANL/ORNL)

8

ANL Single-Cylinder Engine Geometry:CR (-) 12.5:1*Disp. (L) 0.63Bore x Stroke (mm x mm)

89.04 x 100.6

Injection PFI orDI (central)

ORNL Single-Cylinder Engine Geometry:CR (-) - base 10.1:1*Disp. (L) 0.40Bore x Stroke (mm x mm) 79 x 81

Injection DI (central)Or PFI

*Assume a 2-step VCR mechanism• Noted in 2018 ACEC Roadmap• Collaborate with toolkit team to accelerate

*Fixed compression ratio (CR) Perform testing at 12.6:1 and 15:1 CR

Utilize Co-Optima Core fuels and custom blends as needed

Technical Accomplishments Summary

9

• DISI @ SNL• Finished knock tests for a total of 9 fuels.• Used uncertainty modeling to assess

applicability of Octane-Index framework. Identified outliers like 2-butanol.

• Assessed relevance of PMI for 9 fuels across 3 well-mixed and 2 stratifiedoperating strategies.

• Identified that alcohols and cooler engine conditions can induce shortcomings of PMI for soot predictions.

• Developed and used RIM diagnostics for fuel-film thickness measurements.

• Acquired mixed-mode combustion data for 5 fuels, spanning φ, Pin, Tin and [O2].

• Performed assessment of Octane-Index framework for ultra-lean conditions.

• Applied CHEMKIN to determine underlying autoignition sensitivities to intake [O2].

• Numerous technical publications.

• CFD @ ANL• Expansion of merit function analysis • New understanding of thermal stratification

on sequential autoignition • Validated spray and detailed motored flow

with fuel injection for SNL DISI • G-equation combustion model used for

lean-dilute combustion

• Multi-Mode @ ANL and ORNL• Minimum temperature allowing stable low

load HCCI combustion (ANL)• Maximum temperature still allowing knock-

free high load SI combustion (ANL)• ∆T metric for low load ACI and High load

SI (ANL)• Exploration of effect of multi-mode

constraints and impact of range/ location of ACI mode (ORNL)

ACCOMPLISHMENTS (0/11)

Accomplishments (SNL)Stoichiometric Knock Limits for 9 Fuels

10

• Intake-pressure sweeps reveal how fuels respond to load and engine conditions.

• Load-transient operation (dashed lines) allows more advanced CA50 due to cooler in-cylinder conditions.

• For boosted transient operation, K is highly negative. Here, fuels with high RON-MON sensitivity (S)show great benefits.

• RON, MON and knocklimits all have quantifiableuncertainties.

• Performed Monto-Carlo simu-lations to assess robustness of Octane Index.

• Highly negative K becomes uncertain.– OI-based efficiency assessment remains useful.

• Iso-butanol and 2-butanol blends perform betterthan RON & S indicate; Cycloalkanes worse.– Uncertainly quantification suggests real fuel effects.

RON MON

ACCOMPLISHMENTS (1/11)

0

1

2

3

4

5

0.0 0.3 0.6 0.9 1.2 1.5 1.8PM Index [-]

Ave

rage

Soo

t PM

[mg/

m3]

Transient, Tin =30C,Pin = 78 - 147 kPaSteady, Tin = 30C,Pin = 60 - 100 kPaSteady, Tin = 90C,Pin = 60 - 100 kPa

φ = 1.0, 1400 rpm

E30 H

CO

Hig

h A

rom

atic

Alk

ylat

e

Hig

h O

lefin

s

2-B

utan

olIs

obut

anol

DIB

21HoV 38

2423

E10

RD

5-87

27

Accomplishments (SNL)Assessment of PMI for Various Modes of Operation

11

• How well engine-out soot scales with PMI was assessed for 9 fuels over 3 stoichiometric and 2 lean stratified-charge SI operating modes.

• Alcohol-containing fuels cause deviations.– E.g. E30 & E10 for stratified operation.– PMI does not account for oxygen content.

• High Olefin and Di-isobutylene blendsshow high variability between oper. conds.

• Spray-vessel experiments show strong fuel effects on spray and vaporization.– PMI does not account for spray variations. 0

1

2

3

4

5

Soot

PM

[mg/

m3 ]

1000 rpm, Pin = 100 kPa2000 rpm, Pin = 130 kPa

Alk

ylat

e

E30

Stratified SI Operation

Hig

h A

rom

atic

Hig

h C

yclo

-al

kane

s

DIB

Isob

utan

ol2-

But

anol

HO

E10

RD

5-87

Pool fires for non-boosted operation.

DIB Blend High-Olefin

Lingering fuel from 2nd

injection

3rd injection

SNL Collaboration with Skeen et al.

ACCOMPLISHMENTS (2/11)

• Developed and used innovative LED-based side illuminationfor quantitative fuel-film thickness measurements.

• In-situ calibration yields relationship between relativereduction in back-scattered light and film thickness.

• Applied diagnostics to wide ranges of operating conditions,supporting interpretation of PMI efficacy and soot-production pathways.

– Increased Pin strongly reduces wall wetting for E30.– Reduction of Tcoolant strongly increases wall wetting and smoke for E30.

• RIM will be applied for cold-start testing, as out-lined by ACEC Tech Team.

Accomplishments (SNL)Development and Use of Wall-Wetting Diagnostics

Side-based LED

Illustrations by X. He, Beijing Institute of Technology.

Cross section of piston

Tcoolant = 45 60 90 °CSmoke = 1.14 0.69 0.068 FSN

TD

C

12

ACCOMPLISHMENTS (3/11)

Accomplishments (SNL)Mixed-mode Combustion for 5 Fuels

13

• Established stratification approach to stabilize ultra-lean mixed-mode combustion.– Settled on 1.6 mg pilot. 3.6 mg in example.

• Use strong CA50 control authority toachieve stable end-gas autoignition for CA10-90 < 30°CA ⇒ 20% rel. eff. gain.

• Acquired data for ranges of φ, Pin,Tin and [O2].

• Octane-index ranking holds to first order.

-360 -320 -280 -240 -200 -160 -120 -80 -40 0 40 80Crank Angle [°CA ATDC]

Partial Fuel Stratified Lean

RD5-87High OlefinsHigh AromaticHigh CycloalkanesAlkylate

171031N

-100

102030405060

-10 0 10 20 30 40 50 60 70 80 90 100

110

Mass Burned [%]

AH

RR

[J/°C

A]

High Cycloalkane Fuelφ endgas = 0.50

Stable Deflagration

End-gas Autoignition

13

ACCOMPLISHMENTS (4/11)

ANL: Advanced modeling efforts to enhance understanding and accelerate development

14

Expanding Merit Function analysis to new engines/operating points• ORNL multi-cylinder engine (see SI

Combustion part I For more results)• Knock-limited mid-load point

Thermal stratification can result in sequential auto-ignition• Process relevant to both knock and SACI• Providing information to more

accurately model Sandia DISI engine with low-dimensional tools o FT052: Fuel Kinetics

& Simulation - for details

Temperature in the end-gas at CA50 - Sandia DISI engineTwo planes approximately parallel to the pent-roof and through the center of the propagating flame.

Spark gap +

ACCOMPLISHMENTS (5/11)

ANL DISI results: Furthering understanding of flow and mixing details

15

Experiment Simulation

CA10 3.4° 3.5°

CA50 11.9° 14.0°

CA90 23.7° 35.9°

Validated spray and detailed motored flow with fuel injection

• Spray validated with data from Blessinger et al.• 4.0% root mean square error in pressure• Results can be accelerated with confidence

Experiment Simulation

G-equation combustion model able to match experimental pressures• Uses a tabulated approach for robust

flamespeeds at lean/dilute conditions• Important moving forward for MM

ACCOMPLISHMENTS (7/11)

ANL: Fuel Properties which Enhance Mixed-Mode ACI/SI Engine Operation

16

Minimum temperature allowing stable low load HCCI combustion• Preliminary results of testing with three

co-optima core fuels show a weak corelation between fuel’s octane sensitivity and intake temperature requirements for low-load HCCI operation

• At 1500 rpm with 1 bar boost pressure, none of the tested fuels allowed stable (CoV < 3%) low-load HCCI operation with up to 175 °C intake temperature

– Higher compression ratio and lower engine speed to be tested in the near future, both expected to lower intake temperature requirements for low-load ACI, but also lower high-load intake temperature tolerance

16

ACCOMPLISHMENTS (8/11)

ANL: Fuel Properties which Enhance Mixed-Mode ACI/SI Engine Operation

17

Maximum temperature still allowing knock-free high load SI combustion• The tested fuels show significantly

different temperature tolerance at high load SI operation

• Observed differences seem to be also affected by fuel properties other than octane sensitivity (HoV effects)

∆T metric for low load ACI and High load SI• Alkylate fuel showed maximum ∆T

requirement of 130 °C• Observed relationship between octane

sensitivity and ∆T requirements suggests that in-cylinder P-T conditions are not high enough to capture fuel sensitivity effect at low load HCCI operation

17

ACCOMPLISHMENTS (9/11)

ORNL Multi-Mode SI-ACI

18

• Understand fuel-property impacts on achieving stratified ACI with requirements of being able to run in SI mode part time

• Knowledge discovery and additional insights through modeling in collaboration with Co-Optima Toolkit development team project (Edwards ORNL)

Links to boosted SI (Sluder) and previous multi-mode R&D provides insights into constraints needed for realistic results

ACIHigher CR

Single-cylinder results inform what is possible for multi-mode ACI speed and load range and location as a function of fuel properties

ACCOMPLISHMENTS (10/11)

• Focus: quantifying the effects of octane number, sensitivity, and heat of vaporization at “SI” and “ACI” compression ratios at prescribed experimental conditions relevant to multi-mode operation.

• The ORNL multi-mode engine will assume a two-step variable compression ratio mechanism to enable mode transitions from SI to ACI which be completed using different custom piston configurations to enable different compression ratios.

• To enable conditions for ACI modes, a custom intake manifold used to enable higher intake temperatures was used

• Strong links to Co-Optima Tool-kit and Fuels Properties team

ORNL: Accelerating development with Tool-Kit and Fuel Properties team

Temperature - Pressure

19

Toolkit team

ACCOMPLISHMENTS (11/11)

Leverages efforts for Sluder1.6L Boosted SI task

Responses to Previous Year Reviewers’ CommentsNote: two new tasks not reviewed last year

20

Comments requiring addressing: ‒ Reviewers noted “…the scope of work is limited to low TRLs, practical

considerations [aftertreatment requirements and transient controls] should be kept in mind …”‒ Initial DISI work did look at in-cylinder and exhaust soot‒ Multi-mode project at ORNL will be engaged with emissions controls and

characterization tasks‒ Engagement with industry on controls and transients – fundamental

results informing the development ‒ A reviewer noted “…while the evaluation of particulate emissions is

extremely valuable for current and near future production engines, it is not clear if the observed PM emissions were a consequence of the differences in the fuel properties or in the operating procedure.”‒ Good suggestion; fuel properties were isolated for five operating

strategies, as shown in Accomplishments

Reviewers noted “approach taken, of running both metal and optical engine experiments with CFD modeling, is very good (noted multiple times) “

Multi-mode comments: ‒Reviewer noted approach adopted in this project not only supports refinement of the Merit Function for LD SI engines, but is also supporting development of diagnostic techniques that can help evaluate and troubleshoot engine operation for mixed-mode combustion regimes. ‒Reviewer commented on the good progress made on Mixedmodecombustion and transition.

Scores and comments from 2017 Annual Merit Review Report| https://www.energy.gov/sites/prod/files/2017/11/f39/05%20-%20Fuel%20and%20Lubricant%20Technologies.pdf

Overall approach:

Leveraging Co-Optima Collaborations:• Strong industry engagement including industry-led external advisory board, monthly

stakeholder phone calls, and annual stakeholder meeting • Collaboration across nine national laboratories, two DOE offices, and thirteen universities

Collaborations

Details in backup slides

15 Industry partners in the AEC MOU • Meet two times a year to share information with industry partners• Other national labs and University partners as well

Task Specific Collaborations [Strong links between task PIs]

SNL ANL - CFD ANL – Multi-mode ORNL – Multi-mode

• General Motors• Funds-in knock project with Toyota.

• Explores effect of deviations from non-dilute stoichiometric operation.

• Westbrook (LLNL) & Cernansky(Drexel)• Use of detailed chemical-kinetics to

predict RON and MON of alternative fuel blends

• Pitz, Mehl & Wagnon at LLNL • Validate surrogate-gasoline

mechanisms.• Identified areas that required

corrections

• Direct with ANL on CFD + many more

• Direct collaborations with SNL on DISI activities

• Convergent Science IncUConn (Prof. Tianfeng Lu) for chemical mechnisim

• Fuel properties for E30 SNL • ORNL engine (Sluder, Yue)

• Ford• ORNL-multi-mode • SNL DISI • Merit-function

development

• Sluder boosted SI task • Toolkit team – Edwards• Kinetics team (Pitz, Wagnon

et al.,) • Fuel properties team (Szybist/

Splitter) • Ford – support for engine

modifications • ANL multi-mode• General Motors

21

E.1.1.3, E.1.1.4 G.2.1 E.1.2.5 E.1.2.6

Remaining Challenges and Barriers

• Developing combined experimental/ modeling approach to identifying fuel property/engine parameter impacts for wide array of ACI approaches suitable for multi-mode operation

• Identifying key fuel properties/engine parameters that provide efficiency, power density, and wide operability for kinetically controlled combustion

• Developing high-fidelity, computationally efficient kinetic and fluid dynamic models and high quality experimental data to validate

• Further work to address barriers in the 2018 ACEC roadmap around high efficiency SI-ACI multi-mode

22

ANL CFD• Develop and validate a CFD approach for

lean SI combustion• Parametric sweeps and/or GSA to identify

influential fuel properties for multi-mode ACI operation using RANS-type turbulence modeling

• Sensitivities to fuel properties at validation points for multi-mode combustion and possibly update merit function [Q4 milestone]

Multi-mode• Identify/define (new) fuel properties that

impact engine performance under ACI operation

• Identify fuel property/engine parameters that:• Improve ACI operability (simplify transient

control/mode switching, expand speed/load range, improve cold start/low load performance)

• Reduce ACI combustion noise and engine-out emissions

SNL Mixed-mode combustion:• Optically investigate fuel effects on flame

structure in end-gas• Use experiments and CHEMKIN to assess

fuel effects on sensitivities to changes of φ, Pin, Tin and [O2].

• Add lower-RON fuels to test matrix, and determine effect on load coverage.

• Examine if there are specific chemical families that reduce applicability of octane-index framework.

SNL Stratified-charge SI operation:• Determine fuel effects on load coverage.• Focus on soot emissions and combustion

stability for high-EGR, low-NOx operation.• Examine optically fuel/load combinations

that have smoke or stability issues.• Expand efforts on load transients, and start

studies on cold-start effects.– Guidelines from ACEC Tech Team.– For both mixed-mode and stratified SI.

Proposed Future Research*

23

*Any proposed future work is subject to change based on funding levels.

Relevance• Longer-term co-development of fuels for advanced SI and SI-ACI multi-mode combustion.

Approach• Multi-lab team, approach spanning optical engine, metal-single engines, CFD

Technical Accomplishments• Completed knock tests for 9 fuels - uncertainty modeling assess Octane-Index framework• Assessed relevance of PMI for 9 fuels across 5 operating strategies• Mixed-mode combustion data for 5 fuels, spanning φ, Pin, Tin and [O2].• New understanding of thermal stratification on sequential autoignition • ∆T metric for low load ACI and High load SI + data for both• Exploration of effect of multi-mode constraints and impact of range/ location of ACI mode

Collaboration and Coordination • Strong industry engagement including industry-led external advisory board, monthly

stakeholder phone calls, and annual stakeholder meeting • Collaboration across nine national laboratories, two DOE offices, and thirteen universities

Proposed Future Research*• Mixed-mode combustion + Stratified-charge SI operation• CFD for accelerating development • Multi-mode programmatic goals +Multi-mode + emission controls

Summary

24

*Any proposed future work is subject to change based on funding levels.

• The experimental work supporting tasks E.1.1.3, E.1.1.4 and G.2.1 was performed at the Combustion Research Facility, Sandia National Laboratories, Livermore, CA. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.

• The CFD + ANL multi-mode work was done by UChicago Argonne, LLC, Operator of Argonne National Laboratory (Argonne). Argonne, a U.S. Department of Energy Office of Science laboratory, is operated under Contract No. DEAC02-06CH11357.

• ORNL multi-mode work was performed at the National Transportation Research Center (a U.S. Department of Energy User Facility), Oak Ridge National Laboratory, Knoxville TN. Oak Ridge National Laboratory is operated by UT-Battelle for the U.S. Department of Energy under contract DE-AC05-000R22725.

Acknowledgements

25

Technical Back-Up Slides

26

ANL: Initial Fuels and test conditions for multi-mode experiments

27

Test Conditions

Fuel Alkylate E30 AromaticRON (-) 98.0 97.4 98.1

MON (-) 96.6 86.6 87.8

Sensitivity (-) 1.4 10.8 10.3

HoV (kJ/kg) 309 536 363

A/Fst 15.1:1 12.9:1 14.5:1

Paraffin (%vol) 3.0 12.9 8.2

I-Paraffin (%vol) 95.8 27.6 38

Aromatics (%vol) 0.7 13.8 39.8

Naphthenes (%vol) 0.02 7.0 8.0

Olefins (%vol) 0.08 5.6 4.5

Oxygenates (%vol) - 30.4 -

Fuels

Condition ACI SINMEP (bar) 3 9

Speed (RPM) 1500 1500

EGR (%) 0 0

CA50 (°aTDC) 8 20.8

DI SOI (°bTDC) 300

DI Pinj (bar) 150

CoV of IMEP (%) 3

MAPO* Limit (bar) 0.35

*Maximum Amplitude of Pressure Oscillations (MAPO)

ANL CFD

28

• Image presented - two planes that are angled ~ along the flame direction

• plane1 and plane2 show a side view with each plane; angled is at an angled view).

• Red iso-surface is the flame over semi-transparent surfaces of the domain

Plane 2Plane 1 Tstrat-angled

• One E10 regular gasoline, and eight RON = 98 fuels were studied in DISI engine at Sandia.

• Octane sensitivity, compositions, boiling points, heat of vaporization and PMI vary greatly.

SNL - Fuel Properties Table

29

E10 RD5-87 Alkylate E30 High Aromatic High Olefin High

CycloalkaneIsobutanol

Blend2-Butanol

BlendDiisobutyl-ene Blend

RON 90.6 98.0 97.9 98.1 98.3 97.8 98.1 98.2 98.3MON 83.9 96.7 87.1 87.6 87.9 86.9 88.0 89.1 88.5

Octane Sensitivity 6.7 1.3 10.8 10.5 10.4 11.0 10.1 9.1 9.8Oxygenates [vol.%] 10.6 0.0 30.6 0.0 0.0 0.0 24.1 28.4 0.0Aromatics [vol.%] 22.8 0.7 13.8 39.8 13.4 33.2 19.0 17.9 20.1Alkanes [vol.%] 48.7 98.1 40.5 46.2 56.4 40.6 53.1 50.1 56.3

Cycloalkanes [vol.%] 12.1 0.0 7.0 8.0 2.9 24.2 0.0 0.0 0.0Olefins [vol.%] 5.9 0.1 5.6 4.5 26.5 1.6 3.8 3.6 23.6

T10 [°C] 57 93 61 59 77 56 63 63 63T50 [°C] 98 100 74 108 104 87 - - -T90 [°C] 156 106 155 158 136 143 111 111 111

Net Heat of Combustion [MJ/kg] 41.9 44.5 38.2 43.0 44.1 43.2 40.6 40.1 43.2

Heat of Vaporization [kJ/kg] 412 308 532 361 333 373 412 415 337

AFR Stochiometric 14.1 15.1 12.9 14.5 14.8 14.5 13.8 13.6 14.7HoV [kJ/kg stoichiometric

charge] 27.3 19.1 38.4 23.3 21.1 24.0 27.9 28.5 21.5

Particulate Matter Index 1.68 0.22 1.28 1.80 1.00 1.54 0.40 0.37 0.47

Co-Optima Core Fuels

• Collaborating with Westbrook (LLNL) & Cernansky (Drexel) on the use of detailed chemical-kinetics to predict RON and MON of alternative fuel blends.– Used RON- and MON-like DISI-engine data

as input to CHEMKIN-PRO.

• Synergistic RON blending reproduced well.

• Non-monotonic MON trend for PRF91 fuel captured.

• Moving on to lean autoignition tosupport mixed-mode combustion.

• Funds-in knock project with Toyota.• Explores effect of deviations from non-

dilute stoichiometric operation.• Knock limits change with φ.

– Trends relate to RON-MON sensitivity.• Insights complement Co-Optima studies

of ultra-lean mixed-mode combustion.

Collaborations (SNL)

30

• CFD– Direct SNL on DISI activities – UConn (Prof. Lu) for chemical mechanism – Fuel properties for E30 SNL – ORNL engine (Sluder, Yue)

• ANL Multi-Mode– Ford– ORNL-multi-mode, SNL DISI

• ORNL Multi-Mode– ANL multi-mode– Sluder boosted SI task – Toolkit team – Edwards– Kinetics team (Pitz, Wagnon et al.,) – Fuel properties team (Szybist/ Splitter) – Ford – support for engine modifications

• Collaborating with Pitz, Mehl & Wagnon at LLNL to validate surrogate-gasoline mechanisms.

• Identified various areas that required corrections, e.g.:– NOx influence on autoignition.– Burn rate of trimethylbenzene.

• Corrected mechanism captures well DISI engine autoignition timings for both stoichiometric and lean conditions for Co-Optima Core fuels.

Collaborations (SNL + ANL/ORNL)

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Fig 1. Comparison of predicted HRR of High Aromatic fuel under autoigniting condition

Fig 2. Comparison between measured and predicted autoignition timing

AEC MOU & ACEC Interactions with industry for project updates and feedback (multiple times per year) Co-Optima • Collaboration across 9 NLs 2 DOE offices • Eight universities• Stakeholders (129 individuals

from 77 organizations)

SNL cont.